201300041 

### National Transportation Safety Board

Washington, DC 20594

Office of the Chairman

March 26, 2013

The Honorable Michael P. Huerta Administrator Federal Aviation Administration Washington, DC 20591

Dear Administrator Huerta:

Thank you for the Federal Aviation Administration’s (FAA) J anuary 15, 20 13, letter to the National Transportation Safet y Board (NTSB) regarding Safety Recommendations A

- 09

- 43,

- 4 4

,

- 46 through

- 51, and

- 53 , stated below. We issued t hese recommendations to the FAA on July 8, 2009, as a result of our investigation of the June 28, 2008, ground fire before engine startup of AB X flight 1611, a Boeing 767

- 200, at San Francisco International Airport, San Francisco, California.

A

- 09

- 43

Require operators to replace electrically conductive combustible oxygen hoses with electrically nonconductive hoses so that the internal hose spring cannot be energized.

A

- 09

- 44

Prohibit the use of electrically conductive combustible oxygen hoses unless the conductivity of the hose is an intentional and approved parameter in the design.

We are encouraged that t he FAA has issued the airworthiness directives (ADs) and completed the evaluation s of several other manufacturers’ oxygen system designs
, and that your agency has concluded that the designs evaluated to date pose no safety concerns. P ending the completion of your reviews and th e issuance of appropriate ADs, Safety Recommendations A

- 09

- 43 and

- 44 remain classified “Open

— Acceptable Response.”

A

- 09

- 46

Require airplane manufacturers and modifiers to provide positive separation between electrical wiring and oxygen system tubing acc ording to, at a minimum, the guidance in Advisory Circular (AC) 43.13

- 1A, “Acceptable Methods, Techniques, and Practices

–Aircraft Inspection and Repair,” and AC 65

- 15, “Airframe and Powerplant Mechanics Airframe Handbook.”2

A

- 09

- 47

Require airplane manufa cturers and operators to ensure that oxygen system tubing in proximity to electrical wiring is made of, sleeved with, or coated with nonconductive material or that the tubing is otherwise physically isolated from potential electrical sources.

The FAA’s requirement for electrical wiring interconnection system (EWIS) maintenance programs , effective March 10, 2011 , completes the FAA’s actions to satisfy these recommendations in an alternate manner; consequently, Safety Recommendations A

- 09

- 46 and

- 47 are cl assified “Closed

— Acceptable Alternate Action.”

A

- 09

- 48

Develop minimum electrical grounding requirements for oxygen system components and include these requirements as part of the certification process for new airplanes and approved supplemental type certificate [STC] modifications to existing airplanes.

A

- 09

- 49

Once electrical grounding requirements for oxygen system components are developed, as requested in Safety Recommendation A

- 09

- 48, require airplane operators and modifiers to inspect their airplanes for compliance with these criteria and modify those a irplanes not in compliance accordingly.

A

- 09

- 50

Develop inspection criteria or service life limits for flexible oxygen hoses to ensure that they meet current certification and design standards.

A

- 09

- 51

Once inspection criteria or service life limits fo r flexible oxygen hoses have been developed, as requested in Safety Recommendation A

- 09

- 50, require airplane operators to replace those hoses that do not meet the inspection criteria or that exceed the service life limits.

Although the FAA believes that e xisting airworthiness standards are adequate for address ing the issues raised in these recommendations, the agency also believes that new policy is needed to clarify compliance with these standards

. We believe that the revised policy and guidance may address the issues for new airplane designs and new STCs, but the se revisions will not mandate a change for airplanes currently in service with previously approved designs

. Pending the development and issuance of those revisions, Safety Recommendations A

- 0 9

- 48 and

- 50 are classified “Open

— Acceptable Response.”3

Regarding Safety Recommendations A

- 09

- 49 and

- 51, we disagree with the FAA that there is not sufficient basis for applying the propo se d revisions to airplanes in service. However, because t he FAA do es not plan to take the actions specified in Safety Recommendations A

- 09

- 49 and

- 51, they are classified “Closed

— Unacceptable Action.”

A

- 09

- 53

Require operators of transport

- category cargo airplanes to install smoke detectors in the supernumerary or simi lar compartment of their airplanes.

We disagree with the FAA that the actions already taken to address the root cause of th e ABX flight 1611 accident are sufficient to prevent further events , and we continue to believe that mandating smoke/fire detection within all existing supernumerary areas and remote crew
rest areas is warrante d. Although the FAA’s policy may constitute an effective response for new installations, similar actions are also needed for existing airplanes. Accordingly , p ending issuance of the policy memorandum, and similar action being taken to address in

- service airplanes, Safety Recommendation A

- 09

- 53 is classified “Open

— Unacceptable Response.”

We encourage you to submit updates regarding these s afety r ecommendation s electronically at the following e

- mail address: correspondence@ntsb.gov . To avoid confusion, please do not submit both an electronic copy and a hard copy of the same response.

Sincerely,

cc: Ms. Camille Mittelholtz, Acting Director Office of Safety, Energy, and Environment Office of Transportation Policy